Control method of dish washing machine

ABSTRACT

A method for controlling a dish washing machine having a steam generator is disclosed. The control method includes initially supplying water into a steam generator to supply stream to dishes and deciding a water replenishment pattern during the steam operation of the steam generator, based on the initial amount of the water in the steam generator, before the steam operation of the steam generator.

This application claims the benefit of Korean Patent Application No. 10-2007-0032115, filed on Mar. 31, 2007, which is hereby incorporated by reference in its entirety as if fully set forth herein.

BACKGROUND

1. Field of the Disclosure

The disclosure relates to a control method of a washing machine, and more particularly, to a control method of a dish washing machine that is capable of more efficiently washing dishes.

2. Discussion of the Related Art

Generally, dish washing machines are known as an apparatus for automatically washing dishes disposed in a washing compartment by spraying water toward the dishes under high pressure, and thus, removing foreign matter such as food residues attached to the surfaces of the dishes.

One of the important factors associated with such a dish washing machine is washability for cleanly removing food residues attached to the surfaces of dishes. In order to achieve an enhancement in washability, it is necessary to increase the force required to remove foreign matter from the surfaces of dishes, namely, the spray pressure of water. However, when the spray pressure of the water is excessively high, the dishes may be damaged or may easily be broken. Furthermore, when the washing of dishes is carried out at an increased spray pressure, the amount of water required in this washing operation is increased.

Also, when water of an increased spray pressure is used, it is necessary to increase the power consumption of a pump used to supply the water.

In addition, water is simply supplied to the dishes, a washing operation of the dish washing machine, and therefore, the washing time is increased.

SUMMARY

Accordingly, a dish washing machine and a control method of the same that substantially obviates one or more problems due to limitations and disadvantages of the related art is highly desirable.

The present invention uses steam in the dish washing machine so as to improve the washing efficiency of the dish washing machine without damage to dishes. The steam serves to soak foreign matter attached to the dishes, and therefore, the steam improves the washing efficiency of the dish washing machine even when water is sprayed toward the dishes at a somewhat low pressure.

In order to supply steam, the dish washing machine according to the present invention includes a steam generator having a heater mounted therein. During the operation of the dish washing machine, the supply of steam through the steam generator is performed several times. The length of each performance may be set to a predetermined period of time. Consequently, it is necessary to replenish the steam generator with water at least once after the initial supply of water into the steam generator.

An advantage of the present invention is to provide a method of replenishing a steam generator, mounted in a dish washing machine, with water. Another advantage is the provision of a dish washing machine that uses the method.

Additional advantages and features of the invention will be set forth in part in the description that follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. These and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

To achieve these advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, a control method of a dish washing machine may include supplying a first amount of water into the steam generator as an initial water replenishment, and deciding a water replenishment pattern for water added to the steam generator during operation of the steam generator, wherein the water replenishment pattern is based on an amount of water present in the steam generator, before operation of the steam generator.

The steam generator may periodically supply steam into a dish washing compartment of the dish washing machine.

The initial water replacement may be carried out for a predetermined period of time or until a water level in the steam generator reaches a predetermined water level.

Replenishments of water to the steam generator, after the initial water replenishment, may be carried out between periodic steam operations.

The first amount of the water may be calculated based on a time required for the temperature of the water present in the steam generator, before operation of the steam generator, to rise from a first predetermined temperature level to a second predetermined temperature level by the operation of a heater of the steam generator before a main washing operation.

The water replenishment pattern may be decided based on the amount of water present in the steam generator, before operation of the steam generator, and a voltage applied to a heater of the steam generator, the heater used to generate steam.

The water level of the water in the steam generator may be measured before the initial water replacement.

The water replenishment pattern may be decided before the performance of a main washing operation.

The water replenishment pattern may include the initial water replenishment when the main washing operation is commenced and additional water replenishments to periodically supply water to the steam generator at predetermined time intervals.

When the amount of water present in the steam generator, before operation of the steam generator, is equal to or less than a first predetermined value, the first amount of water may be supplied during the initial water replenishment, and a second amount of water, less than the first amount of water, may be supplied during additional water replenishments.

When the amount of water present in the steam generator, before operation of the steam generator, is greater than a first predetermined value and not greater than a second predetermined value, a third predetermined amount of water may be supplied to the steam generator during the initial water replenishment and additional water replenishments.

When the amount of water present in the steam generator, before operation of the steam generator, is greater than a second predetermined value and not greater than a third predetermined value, at least one of the initial water replenishment and an additional water replenishment may be omitted.

A fourth predetermined amount of water may be supplied into the steam generator during non-omitted additional water replenishments.

When the amount of water present in the steam generator, before operation of the steam generator, is greater than a third predetermined value, the steam generator may not be operated.

The third predetermined value may be the maximum amount of water that can be supplied to the steam generator.

In one embodiment, a method of operating a dish washing machine having a steam generator may include initially supplying water into the steam generator for generating steam using a heater to periodically supply the steam into a washing compartment of the dish washing machine, and deciding a water replenishment pattern during the operation of the steam generator based on time required for the temperature of the water to rise to a predetermined temperature level by the operation of the heater.

In one embodiment, a dish washing machine may include a tub defining a washing compartment, a sump to hold water, the sump coupled to the tub, a water supply tube coupled to the tub, a steam generator having an output coupled to the washing compartment and an input coupled to the water supply tube via an electrically controlled valve, an electrically controlled heater to convert water to steam, a water level sensor coupled to the steam generator to indicate a water level within the steam generator, a controller in communication with the valve, the heater, and the water level sensor, and a memory. The memory may include a set of instructions to cause the controller to operate the electrically controlled valve to supply a first amount of water into the steam generator as an initial water replenishment, and decide a water replenishment pattern for water added to the steam generator during operation of the steam generator, wherein the water replenishment pattern is based on an amount of water present in the steam generator, before operation of the steam generator.

The heater may be within the steam generator or the sump.

In one embodiment, a dish washing machine having a steam generator may include a tub defining a washing compartment, a sump to hold water, the sump coupled to the tub, a steam generator to supply steam to the washing compartment, means for determining a water level within the steam generator, means for supplying a first amount of water into the steam generator as an initial water replenishment, and means for deciding a water replenishment pattern for water added to the steam generator during operation of the steam generator, wherein the water replenishment pattern may be based on an amount of water present in the steam generator, measured by the means for determining the water level, before operation of the steam generator.

It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principle of the invention. In the drawings:

FIG. 1 is a view schematically illustrating a dish washing machine according to an embodiment of the invention;

FIG. 2 is a flow chart illustrating a control method of the dish washing machine according to an embodiment of the invention;

FIG. 3 is a flow chart illustrating an embodiment of step S200 of FIG. 2;

FIG. 4 is a graph illustrating points in time at which water may be supplied into a steam generator in accordance with the control method of the dish washing machine, according to an embodiment of the invention; and

FIG. 5 is a table illustrating a water replenishment pattern performed in accordance with the control method of the dish washing machine, according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.

The configuration of a dish washing machine according to an exemplary embodiment of the present invention will be described with reference to FIG. 1.

The illustrated dish washing machine 10 may include a case 100 defining the appearance of the dish washing machine, a door 120 for opening or closing the case 100, and a control panel 130 mounted to the case 100 or door 120, to enable the user to manipulate the dish washing machine.

A tub 110 is arranged in the case 100, to define a washing compartment 150 in the case 100, as a space in which dishes are received and washed. A sump 200 for storing water is arranged beneath the tub 110.

A pump 210 for pumping the water stored in the sump 200 and a filter (not shown) for filtering contaminated water are arranged in the sump 200. A first heater 290 may also be arranged in the sump 200, to heat the water stored in the sump 200.

A first water supply tube 250 is connected to the sump 200, to supply fresh water from an external water supply source to the sump 200. A water discharge tube 270 is also connected to the sump 200, to externally discharge the water from the sump 200. A first water supply valve 255 for controlling the supply of water to the sump 200 is arranged in series with the water supply tube 250.

At least one rack is arranged in the interior (i.e., the washing compartment 150) of the tub 110. At least one spray arm is also arranged in the washing compartment 150, to spray the water pumped by the pump 210 toward the at least one rack.

For reference, FIG. 1 illustrates an example in which an upper rack 160 and a lower rack 170 are arranged at upper and lower portions of the washing compartment 150, respectively, and an upper spray arm 230 and a lower spray arm 220 are arranged such that they spray water pumped by the pump 210 toward the upper rack 160 and lower rack 170, respectively.

In addition, a top nozzle 240 may be arranged at a top portion of the washing compartment 150. The top nozzle 240 functions to downwardly spray water pumped by the pump 210 from the top portion of the washing compartment 150.

The dish washing machine according to the illustrated embodiment of the invention is configured not only to spray water into the washing compartment 150 by the pump 210 and spray arms 220 and 230, but also to spray or supply steam to the washing compartment 150. To this end, the dish washing machine includes a steam generator 300 which operates independently of the first heater 290 arranged in the sump 200.

As shown in FIG. 1, the steam generator 300 communicates with the first water supply tube 250 via a second water supply tube 260. The steam generator 300 also communicates with the washing compartment 150 of the tub 110 via a steam supply tube 280. A second water supply valve 265 for controlling the supply of water to the steam generator 300 is arranged in series with the second water supply tube 260.

The steam generator 300 includes a second heater 310 for heating water supplied to the steam generator 300, and a water level sensor 320 for sensing the level of water in the steam generator 300. The water level sensor 320 may sense, for example, a minimum water level and a maximum water level.

The minimum water level is set to protect the second heater 310 of the steam generator 300. On the other hand, the maximum water level is set to prevent the water supplied to the steam generator 300 from overflowing the steam generator 300.

Also, the steam generator 300 may be provided with a steam supply valve 327 for controlling the opening and closing of the steam supply tube 280 to supply steam at a desired time.

In addition, a controller 180 may be provided to control the dish washing machine 10. As known in the art, the controller 180 may be in communication with a memory 190 that may store instructions used by the controller 180 to execute the steps of the methods in accordance with embodiments of the invention. The controller 180 may be electrically coupled to electrically-operating elements, for example, the control panel 130, the pump 210, and the steam generator 300, to control the operation of the dish washing machine 10. For example, the controller 180 may control the first heater 290, the second heater 310, the pump 210, and the steam generator 300 according to the operation mode of the dish washing machine. The operational couplings of are not illustrated in FIG. 1, to avoid clutter. A procedure for controlling the above-specified parts of the dish washing machine according to the operation mode of the dish washing machine will be described below.

Hereinafter, the operation of the dish washing machine with the above-stated construction according to the present invention will be described with reference to FIGS. 1 and 2. For reference, FIG. 2 is a flow chart illustrating a control method of the dish washing machine according to an embodiment of the present invention.

When a user wishes to wash dishes, the user opens the door 120, puts the dishes to be washed in the upper and lower racks 160 and 170, and then closes the door 120. Of course, the user may put a predetermined amount of detergent or rinse into a detergent box (not shown) before closing the door 120.

When an operation signal of the dish washing machine is inputted through the control panel 130, the dish washing machine performs a predetermined washing course.

The washing course, performed by the dish washing machine according to the present invention, includes a preliminary washing operation, a main washing operation, and a rinsing operation.

After the completion of the preliminary washing operation, the main washing operation is performed. After the completion of the main washing operation, the rising operation is performed.

In the preliminary washing operation (S100), water is sprayed toward the dishes, placed in the washing compartment, for example, for a predetermined period of time. As a result, food residues left on the dishes are partially removed from the dishes by the spraying force of the water, and moisture permeates into the foreign matter attached to the dishes such that the foreign matter is soaked in the moisture, and therefore, the foreign matter can be easily removed from the dishes.

In the preliminary washing operation, water, supplied into the sump 200 from the outside, is supplied to dishes without heating the water. That is, low-temperature water is supplied to the dishes. Of course, heated water may be supplied to the dishes in the preliminary washing operation.

After the completion of the preliminary washing operation (S100), the contaminated water is discharged, and then new water is supplied to progress the main washing operation (S300). In the main washing operation (S300), the water is sprayed toward the dishes such that the dishes are cleanly washed. At this time, in order to improve the washing efficiency, steam may be supplied into the washing compartment 150.

Specifically, both water and steam may be sprayed into the washing compartment to wash the dishes (S310) in the main washing operation (S300). At this time, detergent is contained in the water.

As the steam is supplied into the washing compartment in the main washing operation (S300), the foreign matter, attached to the dishes, is efficiently soaked by the steam, which has high-temperature and high-humidity characteristics, and therefore, the washing efficiency is improved. In order to further improve the washing efficiency, the water may be heated by the first heater mounted in the sump 200, and the heated water may be sprayed toward the dishes, in the main washing operation (S300).

In the main washing operation (S300), the water and steam may be simultaneously or alternately supplied or sprayed into the washing compartment 150. In order to supply the heated water and steam simultaneously into the washing compartment 150, it is required to simultaneously operate the first heater 290 mounted in the sump 200 and the second heater 310 mounted in the steam generator 300.

In this case, the power consumption is increased, and the reliability of the dish washing machine is deteriorated. In order to solve this problem, it is possible to alternately operate the first heater 290 of the sump 200 and the second heater 310 of the steam generator 300 such that the heated water and steam can be alternately sprayed toward the dishes.

In the main washing operation (S300), it is required to replenish the steam generator with water, at least once, after the initial supply of water into the steam generator 300, such that the steam is supplied or sprayed into the washing compartment 150.

In the control method of the dish washing machine according to the present invention, the initial supply of water into the steam generator 300 is performed before the commencement of the main washing operation (S300). At this time, the water replenishment pattern is also decided (S200).

In the main washing operation (S300), a water replenishment process (S320) is carried out according to the water replenishment pattern that is decided before the commencement of the main washing operation.

In the control method of the dish washing machine according to an embodiment of the present invention, the water replenishment pattern, in which the steam generator 300 is replenished with water, may be decided based on the initial amount of the water in the steam generator 300 and/or voltage applied to the heater 310 of the steam generator 300.

Here, the initial amount of the water may mean the sum of the volumes of water left in the steam generator 300 and water newly introduced into the steam generator 300 through an initial supply of water, i.e., the amount of water stored in the steam generator 300 just before the steam operation.

If there is no water in the steam generator before the initial supply of water into the steam generator, for example, all the water in the steam generator is discharged in the preliminary washing operation, the initial amount of the water may be equal to the amount of water initially supplied.

FIGS. 1 and 3 to 5 illustrate a process for deciding the water replenishment pattern, which will be described hereinafter in more detail with reference to these drawings.

For reference, FIG. 3 is a flow chart illustrating an embodiment of Step S200 of FIG. 2, FIG. 4 is a graph illustrating an embodiment of the time point at which water is supplied into the steam generator in accordance with the control method of the dish washing machine according to the present invention, and FIG. 5 is a table illustrating an embodiment of the water replenishment pattern performed in accordance with the control method of the dish washing machine according to the present invention.

Before the main washing operation (S300), in which the steam generator 300 is operated, the initial supply of water into the steam generator 300 may be accomplished (S210). At this time, the initial supply of water may be accomplished for a predetermined period of time or until the water level in the steam generator 300 reaches a predetermined water level.

For example, the initial supply of water may be accomplished by opening the second water supply valve 265 for a predetermined period of time and then closing the second water supply valve 265, or opening the second water supply valve 265 until a predetermined water level, for example, the maximum water level, is detected by the water level sensor 320. Consequently, it is determined whether the predetermined period of time has elapsed, or the predetermined water level, i.e., the maximum water level, has been detected, after the commencement of the initial supply of water (S220). The initial supply of water is continued until a final condition is satisfied.

After the completion of the initial supply of water, the water replenishment pattern during the operation of the steam generator 300 may be accomplished based on the initial amount of the water in the steam generator 300.

The amount of water initially supplied into the steam generator 300 may be approximately calculated, for example, by the opening time of the second water supply valve 265. In this case, however, it may be difficult to confirm how much water is left in the steam generator 300 before the initial supply of water. Furthermore, it may be difficult to accurately estimate the initial amount of the water, i.e., the amount of water stored in the steam generator 300, when, for example, a malfunction of the second water supply valve 265 occurs and/or the pressure of the water supplied exceeds some predetermined amount.

As another example, it is possible to estimate the amount of water initially supplied by the maximum water level detected by the water level sensor 320. In this case, however, it may be difficult to estimate the initial amount of the water stored in the steam generator 300 when considering the malfunction of the water level sensor 320 due to the rolling of water (e.g., waves or undulations of the water surface) or the generation of bubbles during the supply of water.

In the control method according to an embodiment of the present invention, therefore, it is proposed to calculate the initial amount of the water in the steam generator 300 based on time required for the water temperature to rise to a predetermined temperature level by the operation of the heater 310.

The temperature of water, introduced into the steam generator 300 through the second water supply valve 265, may be different depending upon various factors, such as the installation environment of the dish washing machine and seasons. However, it is possible to relatively accurately estimate the initial amount of the water based on time required for the water temperature to rise to a predetermined temperature level, when the water temperature is raised by the operation of the heater 310, i.e., time required for the water temperature to rise from a first predetermined temperature level to a second predetermined temperature level, higher than the first predetermined temperature level.

In the control method according to the present invention, therefore, the second heater 310 of the steam generator 300 is turned on to estimate the initial amount of the water, after the completion of the initial supply of water (S230). Subsequently, the controller 180 measures time required for the water temperature to rise to the predetermined temperature level by the operation of the second heater 310, and estimates the initial amount of the water based on the measured time (S240).

When the time required for the water temperature to rise from the first temperature level to the second temperature level is short, it may be estimated that the amount of water initially supplied into the steam generator is small. When the time required for the water temperature to rise from the first temperature level to the second temperature level is moderate, it may be estimated that the amount of water initially supplied into the steam generator is moderate. When the time required for the water temperature to rise from the first temperature level to the second temperature level is long, it may be estimated that the amount of water initially supplied into the steam generator is large. In addition, when the time required for the water temperature to rise from the first temperature level to the second temperature level exceeds a predetermined time limit, it may be estimated that the amount of water initially supplied into the steam generator is excessive.

The respective required time values, necessary to classify the small, large, and excessive amounts of water initially supplied into the steam generator, may be established differently based on various conditions, such as the storage capacity of the steam generator 300 and the output of the second heater 310.

For example, it may be established that if the second heater 310 is operated with a specific output for a specific period of time, then a given initial amount of the water in the steam generator 300 will experience a predetermined temperature rise value. Consequently, when the condition of the second heater, having the specific output for the specific period of time, is decided, it is possible to estimate the amount of water if the predetermined temperature rise value was previously obtained.

On the other hand, the output of the heater 310, mounted in the steam generator 300, is decided. When the voltage applied to the heater 310 is changed, however, the time required for the heater 310 to raise the water temperature from the first temperature level to the second temperature level may be changed, although the same amount of water is heated. Consequently, the amount of water initially supplied may be decided based on the input voltage applied to the heater 310 as well as the time required for the water temperature to rise to the predetermined temperature level.

To this end, the dish washing machine according to an embodiment of the present invention may include a unit that measures a voltage input to the heater 310 and transmits the measured data to the controller 180.

When the initial amount of the water is decided based on the input voltage applied to the heater 310, as described above, the initial amount of the water is calculated based on the required time. In this case, however, the initial amount of the water may be corrected in consideration of the difference between the actual input voltage applied to the heater 310 and the standard input voltage.

On the assumption, for example, that the initial amount of the water is X, the time required for the water temperature to rise from the first temperature level to the second temperature level (e.g., 60 to 85 degrees C.) is Tb, the input voltage actually applied to the heater 310 is Va, the standard voltage under the usage environment of the dish washing machine is V_constant, and the correction constant is K, the initial amount of the water X may be given as, or proportional to:

X=K1×Tb×(1+(Va−V_constant)×K)

Here, the difference between the input voltage Va and the standard voltage V_constant (for example, 120V or 240V) is small. Consequently, in the case that the correction constant K is established to be less than 0.1, the input voltage applied to the heater 310 is reflected as a correction factor, when the amount of water initially supplied is calculated based on the required time Tb, whereby it is possible to obtain more accurate data. Further, K1 plays a role of equating the units and adjusting correct proportionality.

Of course, if there is no water left in the steam generator 300, before the steam operation of the steam generator, the initial amount of the water is equal to the amount of water initially supplied.

After the initial amount of the water is calculated through the above-described method, the controller 180 decides a water replenish pattern based on the initial amount of the water (S250). The water replenish pattern is decided before the commencement of the main washing operation.

Here, the decision of the water replenish pattern (S250) may be made based on the required time and/or the input voltage applied to the heater 310.

The replenishment of the steam generator 300 with water may be carried out between the periodic steam supply operations. In the main washing operation (S300), for example, the steam may be periodically supplied into the washing compartment 150, as shown in FIG. 4. The replenishment of the steam generator 300 with the water may be carried out at the time when the steam supply is interrupted during the periodic steam supply.

For reference, FIG. 4 illustrates that the replenishment of the steam generator with water may be carried out once, after the steam is sprayed twice, in the condition in which the steam and water are alternately sprayed into the washing compartment 150. However, the present invention is not limited by the example of FIG. 4.

On the other hand, the water replenishment pattern may include an initial water replenishment to supply water when the main washing operation is commenced or the steam operation is performed and additional water replenishments to periodically supply water at predetermined time intervals.

The additional water replenishments may include water replenishments between a first additional water replenishment to supply water after the completion of the initial water replenishment and the final additional water replenishment before the completion of the main washing operation (S300), i.e., an N^(th) water replenishment.

FIG. 5 illustrates an embodiment of the water replenishment pattern. Referring to FIG. 5, when the initial amount of the water X is equal to or less than a first predetermined value X₁, a first predetermined amount of water is supplied during the initial water replenishment, and a second amount of water, less than the first amount of water, is supplied during the additional water replenishments.

The reason why a larger amount of water is supplied during the initial water replenishment is that when the initial amount of the water is small the supplying of the first amount may prevent exposure of the second heater 310 to air, during the generation of steam, thereby protecting the second heater 310.

When a large amount of water is replenished during the initial water replenishment, a sufficient amount of water is stored in the steam generator 300 after the completion of the initial water replenishment. For this reason, it is sufficient to replenish the steam generator 300 with only water having an amount equivalent to the amount of the water reduced due to the supply of steam, during the additional water replenishments.

When the initial amount of the water X is greater than the first predetermined value X₁ and not greater than a second predetermined value X₂, a third predetermined amount of water is supplied during the initial water replenishment and the additional water replenishments. This is because an appropriate amount of water is stored in the steam generator 300, before the steam operation, and therefore, it is sufficient to replenish the steam generator 300 with water having an amount equivalent to the amount of the water reduced due to the supply of steam, both initially and during the additional water replenishments.

When the initial amount of the water X is greater than the second predetermined value X₂ and not greater than a third predetermined value X₃, at least one of the initial water replenishment and additional water replenishments is omitted.

For example, only the initial water replenishment may be omitted, or the initial water replenishment and the first additional water replenishment may be omitted, or the initial water replenishment, the first additional water replenishment, and the second additional water replenishment may be omitted.

During the remaining water replenishments, not omitted, a fourth predetermined amount of water is supplied into the steam generator 300.

This is because, when the initial amount of the water is large, a sufficient amount of water is left in the steam generator 300, although the supply of steam is periodically performed several times without the water replenishments. Also, it is sufficient to replenish the steam generator 300 with water having an amount equivalent to the amount of the water reduced due to the supply of steam at the time point when the water in the steam generator 300 is insufficient after the water replenishment is omitted at least once or several times.

When the water replenishment is omitted at least once or several times in the case that the initial amount of the water is large, it is possible to prevent the water temperature in the steam generator 300 from greatly lowering due to the water replenishment, thereby rapidly producing steam and saving energy. When the water is continuously replenished, although the initial amount of the water is large, the water temperature in the steam generator 300 greatly lowers with the result that a relatively long amount of time is necessary before steam may be produced. Consequently, energy consumption is also increased. In addition, the water supplied through the water replenishment is prevented from overflowing the steam generator 300.

Also, when the initial amount of the water X is greater than the third predetermined value X₃, the steam generator 300 is not operated. Here, the third predetermined value X₃ corresponds to the maximum supply amount of water.

This is because, when the initial amount of the water exceeds the maximum supply amount of water, it is estimated that the second water supply valve 265 or the water level sensor 320 is operating in an abnormal manner, and, in this case, therefore, it is not possible to normally perform additional water replenishments.

Consequently, when it is estimated that the initial amount of the water is excessive, the operation of the steam generator 300 is terminated. However, the operation of other parts of the dish washing machine, excluding the steam generator 300, for example, the water spraying process by the pump 210, are performed, according to schedule, irrespective of the termination of the operation of the steam generator 300.

This is because the supply of the steam is an auxiliary means to improve the washing efficiency of the dish washing machine, and therefore, when the steam generator 300 is operating in an abnormal manner, the operation of the steam generator 300 is terminated; however, the water spraying process is continuously carried out to complete the predetermined dish washing course.

The reference values for the initial amount of the water, i.e., the first predetermined value X₁, the second predetermined value X₂, and the third predetermined value X₃, may be decided based on the capacity of the steam generator or the water level in the steam generator.

Also, the first amount of water, the second amount of water, the third amount of water, and the fourth amount of water may be decided based on the steam operation time or the capacity of the steam generator. Here, the first amount of water may be established such that the first amount of water is greater than the second amount of water, the third amount of water, or the fourth amount of water. Also, the second amount of water, the third amount of water, and the fourth amount of water may be the same as the others. Alternatively, at least one of the second amount of water, the third amount of water, and the fourth amount of water may be different from the others.

Also, the water level sensor, mounted in the dish washing machine according to the present invention, may detect the water level of the water left in the steam generator before the initial supply of water into the steam generator. When it is determined, as a result of detecting the water level, before the initial supply of water, that the amount of water is greater than the third predetermined value, the controller 180 may terminate the operation of the steam generator 300, thereby improving the reliability of the steam generator 300.

Meanwhile, the main washing operation (S300) is carried out including the water and steam spraying process and the replenishment of the steam generator with water. When the water is excessively contaminated, during the main washing operation (S300), the discharge of the contaminated water and the supply of new water may be performed several times. After the completion of the predetermined main washing operation (S300), the contaminated water is discharged, and new water is supplied to rinse the dishes (S400).

During the rinsing operation (S400), the rinse water may be clean water. During the rinsing operation (S400), the clean water is sprayed toward the dishes to wash any foreign matter, which may have reattached to the dishes after a previous wash or rinse, from the dishes.

Even in the rinsing operation (S400), the heater (290) of the sump 200 may be operated such that the heated water can be sprayed toward the dishes. After the dishes are rinsed for a predetermined period of time (S400), the dish washing machine may produce a predetermined audible alert (e.g., a beep sound) to inform the user that the washing course has been completed.

Thus, it is intended that the present invention covers the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.

As apparent from the above description, the present invention has the effect of improving the dish washing efficiency through the use of steam.

In addition, the water replenishment is carried out to replenish the steam generator of the dish washing machine with only a required amount of water. Consequently, the present invention has the effect of effectively preventing the delay of steam generation due to the unnecessary supply of water and the waste of energy. Also, the steam is supplied into the washing compartment at the optimum time during operation of the dish washing machine 10. Consequently, the present invention has the effect of improving the washing efficiency.

Furthermore, the dishes are washed in various manners using steam and water. Consequently, the present invention has the effect of further improving the washing efficiency.

It will be apparent to those skilled in the art that various modifications and variations can be made from the embodiments described herein without departing from the spirit or scope of the invention. Thus, it is intended that the claims appended hereto cover the modifications and variations. 

1. A method for controlling a dish washing machine having a steam generator, comprising: supplying a first amount of water into the steam generator as an initial water replenishment; and deciding a water replenishment pattern for water added to the steam generator during operation of the steam generator, wherein the water replenishment pattern is based on an amount of water present in the steam generator, before operation of the steam generator.
 2. The method according to claim 1, wherein the steam generator periodically supplies steam into a dish washing compartment of the dish washing machine.
 3. The method according to claim 1, wherein the initial water replacement is carried out for a predetermined period of time or until a water level in the steam generator reaches a predetermined water level.
 4. The method according to claim 2, wherein replenishments of water to the steam generator after the initial water replenishment are carried out between the periodic steam operations.
 5. The method according to claim 1, wherein the first amount of the water is calculated based on a time required for the temperature of the water present in the steam generator, before operation of the steam generator, to rise from a first predetermined temperature level to a second predetermined temperature level by the operation of a heater of the steam generator before a main washing operation.
 6. The method according to claim 1, wherein the water replenishment pattern is decided based on the amount of water present in the steam generator, before operation of the steam generator, and a voltage applied to a heater of the steam generator, the heater used to generate steam.
 7. The method according to claim 1, further comprising: detecting the water level of the water in the steam generator before the initial water replacement.
 8. The method according to claim 1, wherein the water replenishment pattern is decided before the performance of a main washing operation.
 9. The method according to claim 8, wherein the water replenishment pattern includes the initial water replenishment when the main washing operation is commenced and additional water replenishments to periodically supply water to the steam generator at predetermined time intervals.
 10. The method according to claim 1, wherein, when the amount of water present in the steam generator, before operation of the steam generator, is equal to or less than a first predetermined value, the first amount of water is supplied during the initial water replenishment, and a second amount of water, less than the first amount of water, is supplied during additional water replenishments.
 11. The method according to claim 1, wherein, when the amount of water present in the steam generator, before operation of the steam generator, is greater than a first predetermined value and not greater than a second predetermined value, a third predetermined amount of water is supplied to the steam generator during the initial water replenishment and additional water replenishments.
 12. The method according to claim 1, wherein, when the amount of water present in the steam generator, before operation of the steam generator, is greater than a second predetermined value and not greater than a third predetermined value, at least one of the initial water replenishment and an additional water replenishment is omitted.
 13. The method according to claim 12, wherein a fourth predetermined amount of water is supplied into the steam generator during non-omitted additional water replenishments.
 14. The method according to claim 1, wherein, when the amount of water present in the steam generator, before operation of the steam generator, is greater than a third predetermined value, the steam generator is not operated.
 15. The method according to claim 14, wherein the third predetermined value is the maximum amount of water that can be supplied to the steam generator.
 16. A method for controlling a dish washing machine having a steam generator, comprising: initially supplying water into the steam generator for generating steam using a heater to periodically supply the steam into a washing compartment of the dish washing machine; and deciding a water replenishment pattern during the operation of the steam generator based on time required for the temperature of the water to rise to a predetermined temperature level by the operation of the heater.
 17. A dish washing machine, comprising: a tub defining a washing compartment; a sump to hold water, the sump coupled to the tub; a water supply tube coupled to the tub; a steam generator having an output coupled to the washing compartment and an input coupled to the water supply tube via an electrically controlled valve; an electrically controlled heater to convert water to steam; a water level sensor coupled to the steam generator to indicate a water level within the steam generator; a controller in communication with the valve, the heater, and the water level sensor; and a memory, wherein the memory comprises a set of instructions to cause the controller to: operate the electrically controlled valve to supply a first amount of water into the steam generator as an initial water replenishment; and decide a water replenishment pattern for water added to the steam generator during operation of the steam generator, wherein the water replenishment pattern is based on an amount of water present in the steam generator, before operation of the steam generator.
 18. The dish washing machine of claim 17, wherein the heater is within the steam generator.
 19. A dish washing machine having a steam generator, comprising: a tub defining a washing compartment; a sump to hold water, the sump coupled to the tub; a steam generator to supply steam to the washing compartment; means for determining a water level within the steam generator; and means for supplying a first amount of water into the steam generator as an initial water replenishment; and means for deciding a water replenishment pattern for water added to the steam generator during operation of the steam generator, wherein the water replenishment pattern is based on an amount of water present in the steam generator, measured by the means for determining the water level, before operation of the steam generator. 